Above is a table of all the cool things you have access to via the
Request.ServerVariables collection. Now, I know what you're thinking:
"What do server variables have to do with any of this information?" Well,
I don't know, but what I do know is that all of the HTTP header information
that is sent by the client's browser to your server is available via this
collection. You did catch that part about the client's browser....yes
folks, some of these variables are browser specific! Luckily most of them
are pretty well standardized. Just don't go using something like
"HTTP_UA_PIXELS" and you'll be fine (It only works in old versions of IE!).
Look at all the info we can get! You'll notice some of these are empty.
Many of them only contain data in certain situations. For instance, all
the variables that start with "CERT_" have to do with authentication
certificates. Since we aren't using any on this site, these fields are
naturally blank. The same goes for the "HTTPS_" and "AUTH_" groups of
One other thing to note is that this script display all of the variables
that currently exist. So, if you fire up a browser different from
the one you're using now, you may gain and/or lose some of the variables
listed above. In other words, this isn't a comprehensive list of all
possible server variables, it's simply a list of the ones that the
combination of your browser and our server makes available.